This invention relates to manometers and more particularly to a liquid manometer for measuring body fluid pressure.
Body fluid pressure indicating devices, such as direct venous pressure manometers, generally include a manometer tube with a scale which is connected to an intravenous catheter disposed in a vein of the patient. The level of liquid in the tube indicates the pressure of the blood in the vein. Central venous pressure (CVP) is often monitored during post-surgery therapy and is generally accompanied by intravenous administration of a liquid such as a saline solution. Central venous pressure may be monitored, for example, by measuring blood pressure in the superior vena cava or subclavian vein.
Such manometers are generally packaged in individual containers which may be in the form of wrappers or boxes. The packaged manometer may contain an extension tube and a three-way stopcock or valve for connecting the manometer in a blood pressure measuring and liquid infusion system. Also, in some cases, an attached sighting device is included for the purpose of accurately adjusting the position of the manometer is relative to the patient so that the zero reading on the manometer scale is at the same level as the right atrium of the heart of the patient in order to obtain correct readings. U.S. Pat. No. 3,934,576 illustrates the use of a three-way stopcock and of a sighting device connected to a manometer.
Such packaged manometers have certain disadvantages. For example, when the manometer is to be used, the container or packaging material must be removed from the manometer and then discarded such as by placing it into a waste receptacle. The packing container, in some cases, represents a significant portion of the total cost of the manometer. Also, the sight means may add significantly to the cost of the device.